If you are looking for an LED bulb to replace a 40 Watt incandescent, the General Electric Energy Smart LED might be the choice for you. While consuming 9 Watts, the GE LED bulb puts out 450 lumens of light in an omnidirectional pattern that emulates a typical incandescent bulb. This true omnidirectional light pattern is the feature that sets this bulb apart from many other bulbs that emit light in a more directional fashion.
The design of the bulb is unique among LED bulbs in that its cooling fins extend up and around the glass envelope that covers the light emitting diodes. These fins serve not only to cool the hot-running LEDs, but also to protect the bulb in the event that it is dropped.
This is the coolest running LED bulb that I have tested so far. Most bulbs run at about 160º-170º, but the GE LED bulb runs at about 135º at the base, and considerably cooler at the tips of the cooling fins.
As for efficiency, the bulb is rated at 450 lumens and 9 watts. Doing the math, we find that this is only 50 lumens per Watt which is quite poor from an energy consumption standpoint. Nonetheless, this bulb has received the Energy Star logo on its packaging.
The light color is rated at 3000K on the packaging. By my eye, it seems to hold up to that rating.